Regular vs Premium Gas

From reading the manual, it's my understanding that you're supposed to fill the Micra with regular gas. However, my dad has been encouraging me for months to fill up with premium instead because it's better/cleaner for the engine and also helps with fuel economy (you get a tank of gas for longer than with regular). I have noticed that after filling with premium, I do get a bit better mileage.

Is it okay to fill a car with premium even though the manual says regular? My dad has been driving for a long time and I do consider his opinion but I wanted to get some other opinions. He's pretty adamant about only filling the Micra with premium.

I have had my Micra a year and 3 months, very low milage car not quite to 9000km yet. Up until last week i always filled up with premium. There have been a few heated debates here on the forum on the premium/regular question and after looking on line at a bunch more info, debates and technical discussions, i have decide to try running regular gas to see if there is any difference i can notice with regards to mileage or performance.

I am at a little over half a tank and so far no noticable difference anywhere (except the price).

But using a higher octane fuel than a vehicle’s owner’s manual specifies “provides no increase in fuel economy, horsepower or a reduction in emissions,” said Greg Brannon, the AAA’s director of automotive engineering.

The extra octane acts as a catalyst for combustion in a high compression engine. If the manual doesn't call for premium don't waste your money!